# Finding the impedance of a circuit

• Engineering

## Homework Statement

http://img297.imageshack.us/img297/2951/picqk5.th.jpg [Broken]

I'm just trying to do part a for the moment.

## The Attempt at a Solution

My initial attempt was just trying to find the impedance of the 5 mH inductor and saying that would be Zin. Unfortunately that doesn't seem to be the case.

Then I tried doing a thevenin type problem where I find the impedance of all the elements to the right of the inductor, but that doesn't seem to work either.

I also just tried finding Zeq for the whole thing but that doesn't work either, hmm.
How does one find the impedance between two nodes? I would have thought that the 2nd method would have worked for sure.

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Thevenin Theorem should work here. Find the equivalent impedance seen from the nodes a and g.

(Hint : Fold from the right side to the left side)

CEL
No need to use Thevenin, since there is no power source.
Between nodes b and g there are two elements. Find the impedance of the parallel combination. Between nodes a and b there is a capacitor, that is in series with the impedance bg. Finally, calculate the impedance of the three branches in parallel between nodes a and g.
A similar reasoning can be made for items b and c.